Causes of Autism

There are various theories as to what causes the different forms of autism - including Asperger syndrome, autistic disorder and pervasive developmental disorder (not otherwise specified).

Most researchers believe that autism has a variety of causes.

Medical Research Council

'Research over the last half century has established autism as a neurodevelopmental disorder. Early suggestions that ASDs might result from abnormal parenting have been abandoned in the face of overwhelming evidence for a biological basis and a strong genetic component. Most researchers believe that ASDs have a variety of causes, perhaps all affecting the same brain systems, or impeding development through disruption of different abilities necessary for social and communicative development.Whether environmental factors interact with genetic susceptibility is as yet unclear.'

National Autistic Society

'The causes of autism are still being investigated. Many experts believe that the pattern of behaviour from which autism is diagnosed may not result from a single cause. There is strong evidence to suggest that autism can be caused by a variety of physical factors, all of which affect brain development - it is not due to emotional deprivation or the way a person has been brought up.

'There is evidence to suggest that genetic factors are responsible for some forms of autism. Scientists have been attempting to identify which genes might be implicated in autism for some years.'

Autism Society of America

'There is no known single cause for autism, but it is generally accepted that it is caused by abnormalities in brain structure or function. Brain scans show differences in the shape and structure of the brain in autistic versus non-autistic children. Researchers are investigating a number of theories, including the link between heredity, genetics and medical problems. In many families, there appears to be a pattern of autism or related disabilities, further supporting a genetic basis to the disorder. While no one gene has been identified as causing autism, researchers are searching for irregular segments of genetic code that autistic children may have inherited. It also appears that some children are born with a susceptibility to autism, but researchers have not yet identified a single "trigger" that causes autism to develop.'